安卓 编辑已定义的tet，但仍然：尝试调用虚拟方法'android.text.Editable android.widget.EditText.getText（）'

Question

流程：com.example.newquiz，PID：23251 java.lang.NullPointerException：尝试在com.example.newquiz上的空对象引用上调用虚拟方法'android.text.Editable android.widget.EditText.getText（）'。 ResultActivity $ 2 $ 2.onClick（ResultActivity.java:68）

当我尝试执行userInput.getText.ToString（）时，方法OnCLick userInput =（EditText）findViewById（R.id.input_text ）。 请帮忙。 我什至不明白是怎么回事。

public class ResultActivity extends AppCompatActivity {
TextView t, c, w;
Button savescore, retry;
private static Score score = new Score();
DatabaseHelper databaseHelper;
private TextView final_text;
final Context context = this;
EditText userInput;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_result);
    t = (TextView) findViewById(R.id.total);
    c = (TextView) findViewById(R.id.correct);
    w = (TextView) findViewById(R.id.wrong);
    savescore = (Button) findViewById(R.id.savescore);
    retry = (Button) findViewById(R.id.retry);


    Intent i = getIntent();
    String questions = i.getStringExtra("total");
    String correct = i.getStringExtra("correct");
    String wrong = i.getStringExtra("incorrect");
    t.setText(questions);
    c.setText(correct);
    w.setText(wrong);
    databaseHelper = new DatabaseHelper(this);
    retry.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent myIntent = new Intent(view.getContext(), MainActivity.class);
            startActivity(myIntent);

        }
    });
    savescore.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            LayoutInflater li = LayoutInflater.from(context);
            View promptsView = li.inflate(R.layout.name, null);
            AlertDialog.Builder mDialogBuilder = new AlertDialog.Builder(context);
            mDialogBuilder.setView(promptsView);
            userInput = (EditText) findViewById(R.id.input_text);

            mDialogBuilder
                    .setCancelable(false)
                    .setPositiveButton("Save",
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    score.setName(userInput.getText().toString());
                                    databaseHelper.insertLeaderboard(score);


                                    Intent i = new Intent(ResultActivity.this, LeaderBoardActivity.class);

                                    startActivity(i);
                                    finish();
                                }
                            })
                    .setNegativeButton("Cancel",
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    dialog.cancel();
                                }
                            });

            //Создаем AlertDialog:
            AlertDialog alertDialog = mDialogBuilder.create();

            //и отображаем его:
            alertDialog.show();

        }
    });
}


@Override
public void onBackPressed() {
    new AlertDialog.Builder(this)
            .setTitle("Exit")
            .setMessage("Do you really wanna close quiz?")
            .setNegativeButton(android.R.string.no, null)
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface arg0, int arg1) {

                    ResultActivity.super.onBackPressed();
                }
            }).create().show();
}


public static Score getScore() {
    return score;
}

}